With increasing popularity of mobile voice and data communication, there is an ever increasing demand for high-speed data communication. User equipment configured to connect to a communication network, e.g. smartphones, have advanced processing capabilities.
For battery powered user equipments, power consumption is of significant importance in order to increase battery lifetime. For certain use cases, the total battery lifetime requirements may be challenging to meet. One exemplary scenario which imposes demanding battery lifetime requirements is machine-to-machine (M2M) communication.
To reduce modem power consumption, the user equipment may be set to different states. For illustration, 3GPP specification TS 25.331 V12.1.0 (2014-03) entitled “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC); Protocol specification (Release 12)” defines different RRC states in sections 7.1 and 7.2. The mobile terminal may enter some of these states autonomously, e.g. when a timer expires.
A further reduction in power consumption may be achieved when the user equipment has a power saving state in which an access stratum (AS) layer of the user equipment is deactivated. The user equipment may stop performing or may reduce AS functions such as monitoring paging and system information, performing measurements and cell reselection procedures in the network. The user equipment may optionally perform tracking area update (TAU) procedures or other procedures in a periodic manner.
Such a power saving state improves power consumption and increases the battery lifetime. However, one problem associated with the power saving state is that the user equipment may not be reachable for the cellular communication network when the user equipment is in this state. Some user equipments may have long sleep periods which, e.g. sleep periods in excess of one hour, sleep periods in excess of one day or even sleep periods in excess of one month. Typical examples include machine-to-machine (M2M) terminals. For illustration, some M2M terminals may provide a machine reading only once in several months. If an operator wants to perform an update on the M2M terminal, e.g. a software or firmware update, the operator may need to wait for a long period until the M2M terminal re-attaches to the cellular communication network and the update can be performed.